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For most ute owners, off-roaders, and 4×4’ers, dual battery setups have been standard fare for a long time. After all, if having the battery power to run a fridge and a handful of lights at night makes spending a night in the outback less of an inconvenience, then having enough power in the morning to start the engine isn’t too bad either.
It’s called battery isolation, the distinction between simply adding a second battery and having a true dual battery set-up. But no matter what your battery-powered objective is, your first step still starts off with having the right tray and hardware to get a battery mounted.
Battery tray basics
It may come as a surprise, but any discussion about multi-battery setups needs to begin with stability because although dual setups are most commonly associated with off-roaders, it’s by no means an undertaking that’s exclusive to off-roading. Monster audio installers also rely on multi-battery setups in daily-drivers to drive their ground shaking wattage. So, the expectations for both truck and car battery trays are primarily their stability and their reliability and as such they can’t be ignored.
First and foremost, battery trays have to be strong, stable and corrosion resistant. And if there’s any wonder why, then you need to remember that the electrolytic fluid in flooded batteries is no less than 37% sulfuric acid. It’s nasty stuff if it’s given a chance to splash around on its own accord.
An improperly secured battery can become the equivalent of a 20kg hammer flailing around under the bonnet. That’s why a battery tray that’s been MIG welded from 2mm steel and powder-coated is going to put a solid enclosure under and around an auxiliary battery. Stainless steel fasteners eliminate the headache of hardware corrosion.
Above all, having one that fits the confines of a specific vehicle’s engine compartment ensures the battery starts in, and stays in, the best location possible. A cheap generic tray or battery box can’t provide the assurance of one that’s designed to match precise under-the-bonnet contours and dimensions. A proper fitting tray’s going to use factory drilled holes, braces, and body well recesses. That’s the reliability you want a tray to have.
Tray placement
When it comes to tray placement, there doesn’t need to be any guesswork when you’re going to mount it and getting the right kit from the start makes everything safer and easier. Under-bonnet real estate generally comes at a premium though, and if you’ve mounted anything else under the bonnet that’s appropriated some of the space that would be used by a correctly fitted battery tray holder, then you might need to look for an alternate location.
Under-bonnet goodies like aftermarket snorkels, or the addition or modification of plumbing for air conditioners, or other powered accessories, are notorious space gobblers. Ultimately, you may need to rethink tray placement, and if you do, there are some conditions you want to be mindful of.
· Proper battery ventilation
You don’t want to locate, or relocate, a battery to any location where it won’t get sufficient ventilation. Airflow is essential for preventing hydrogen gas build-up.
· Level surfaces
If you’re contemplating ways to “squeeze” a tray into position around some of those accessories that would leave it unlevelled, then you need to find a way to get it levelled. The cells inside an unlevelled battery won’t be adequately covered, and spills and slippage are possible.
· Heat buildup
Batteries don’t like heat. That’s why you want to avoid areas that are too close to headers, turbos, or anywhere that high temperatures can contribute to excessive electrolyte evaporation.
Auxiliary battery line-up
Ideally, a good battery tray is going to allow you to make use of the largest possible battery to deliver the most amps. While all the big numbers may look good though, you still don’t want to forget that there are genuine differences between multi-battery setups.
· Dual battery systems
These setups are intended for making life off the grid more comfortable. By isolating the battery that’s responsible for powering fridges, lights, and other devices, you’re assured of always having a battery that’s ready to start the engine. The wiring in these setups is extremely critical, however, as both batteries need to be charged (either from your alternator or an external source) without the opportunity for either battery to steal a charge from the other.
· Secondary battery systems
These setups are commonly used for high powered audio and mobile service activities where multiple batteries are not only expected to provide their power simultaneously, but to take their charge simultaneously too. These systems lack the charging nuances of dual systems, and depending on what needs to be powered, the batteries can simply be wired either in series or parallel configuration without the need for advanced battery management.
The right battery
Once you’ve decided on the best and safest location to mount your auxiliary, the last thing to consider is which battery is actually going to be right. It still may not be the biggest, even if the tray can accommodate it.
· Cranking batteries
These batteries like to deliver a lot of amps in short periods, and they like being recharged quickly. What they don’t like is being heavily discharged. Also, providing hours of power to a host of accessories isn’t the position they’ll want to be in.
· Deep cycle batteries
These batteries are best at providing continuous power for long periods. They aren’t bothered by deep discharging, and to match their slow, low amp outputs, they also prefer slow recharges. This makes them pretty optimal for overnight, off-roading occasions.
The conclusion
At the end of the day, regardless of the type of battery you choose, your choice of car battery trays, as unassuming as they may be, is actually a pretty big one. If you can imagine a tray strictly as a means of supporting an extra battery, then you can also imagine what can happen if it isn’t adequately secured and held in position.
That’s why regardless of whether you need that extra juice for a truck or car battery, trays deserve careful consideration. If you’re contemplating adding an auxiliary battery to your ute or 4×4, make sure to get a tray that’s been designed to fit your vehicle. It won’t just give you a consistent supply of power, it’s also guaranteed to give you peace of mind.
